Comparison of Laser-Synthetized Nanographene-Based Electrodes for Flexible Supercapacitors

Francisco J Romero,Noel Rodriguez,Raul Romero,Diego P Morales,Carmen L Moraila-Martinez,Alfonso Salinas-Castillo,Inmaculada Ortiz-Gomez,Denice Gerardo

doi:10.3390/mi11060555

Francisco J Romero, Noel Rodriguez + Show 6 more

Open Access

https://doi.org/10.3390/mi11060555

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Abstract

In this paper, we present a comparative study of a cost-effective method for the mass fabrication of electrodes to be used in thin-film flexible supercapacitors. This technique is based on the laser-synthesis of graphene-based nanomaterials, specifically, laser-induced graphene and reduced graphene oxide. The synthesis of these materials was performed using two different lasers: a CO2 laser with an infrared wavelength of λ = 10.6 µm and a UV laser (λ = 405 nm). After the optimization of the parameters of both lasers for this purpose, the performance of these materials as bare electrodes for flexible supercapacitors was studied in a comparative way. The experiments showed that the electrodes synthetized with the low-cost UV laser compete well in terms of specific capacitance with those obtained with the CO2 laser, while the best performance is provided by the rGO electrodes fabricated with the CO2 laser. It has also been demonstrated that the degree of reduction achieved with the UV laser for the rGO patterns was not enough to provide a good interaction electrode-electrolyte. Finally, we proved that the specific capacitance achieved with the presented supercapacitors can be improved by modifying the in-planar structure, without compromising their performance, which, together with their compatibility with doping-techniques and surface treatments processes, shows the potential of this technology for the fabrication of future high-performance and inexpensive flexible supercapacitors.

Highlights

Flexible electronics are expected to bring out a revolution in diverse fields of technology, such as electronic skin [1,2], robotics [3,4] or health-monitoring devices [5,6,7], among others
We obtained a total of four different combinations laser-electrode
The layout studied in this work consisted of planar InterDigital Electrodes (IDE) structure (Figure 1), given that this configuration allows to achieve lower thicknesses and a more accurate control of the distances between electrodes than its stack counterpart [36]

Summary

Introduction

Flexible electronics are expected to bring out a revolution in diverse fields of technology, such as electronic skin [1,2], robotics [3,4] or health-monitoring devices [5,6,7], among others. The efforts in this direction have led to extensive investigations on the use of several classes of nanomaterials with different conductivity and sensing capabilities, including carbon nanotubes (CNTs), graphene-derived materials, metal nanowires or conductive polymers [13] All these materials have in common being compatible with printing techniques, which enable their economical and efficient processing on diverse flexible substrates, thereby providing a commercially attractive possibility to obtain multifunctional electronics over large areas [14]. In the case of pseudocapacitors, the most studied materials are transition metal oxides and conducting polymers, which promote the reversible faradaic-type charge transfers of these redox supercapacitors [24], whereas EDLCs electrodes are fabricated from nanoscale materials with high porosity and high surface area In this latter case, carbon-based materials are preferred to play this role, due to their exceptionally high surface area, relatively high electrical conductivity and acceptable cost.

Materials

Fabrication Processes

Results and Discussion

Characterization